In recent years, the game of bingo has gained substantial popularity, and a bingo gaming industry has developed to provide the implements for playing the game. As a result, there has been a significant effort toward the development of improvements in the game playing implements which are intended to make bingo playing easier and more enjoyable.
One significant development in this area was the invention of the see-through magnetically permeable bingo chip. U.S. Pat. No. 4,019,747 to Chuilli disclosed a bingo chip having a magnetic ring positioned at the circumference of a transparent disk or along the interior edge of a donut-like disk. More recently, such a feature was disclosed in U.S. Pat. No. 4,172,597 to Smith, et al wherein a magnetic mesh or screen is sandwiched between plastic sheets. In the industry, this configuration is often referred to as the "Screen Chip". Most recently, U.S. Pat. No. 4,395,043 to Gargione disclosed a bingo chip comprising a disk having a ring crimped about its periphery. In the industry, this configuration is often referred to as the "Ring Chip".
While all of the above mentioned bingo chip structures provide a see-through, magnetic bingo chip, they suffer from a number of drawbacks. With respect to the Screen Chip, pieces of the screen or mesh often protrude beyond the plastic sandwich which can scratch the surfaces of any other chips which may contact the chip during use, or injure the user. Furthermore, the screen itself tends to obscure, to a slight degree, the images which are projected through the chip.
The major drawback of the bingo chip taught by the patent to Chuilli is that its preferred embodiment is difficult to manufacture. The preferred embodiment requires that a ring having an axial thickness less than that of the plastic disk be positioned on the outer edge thereof. In turn, this requires that the outer edge of the disk be capable of supporting the ring. One technique suggested was to knurl the inner surface of the ring so as to provide a frictional-fit between the inner surface of the ring and the outer surface of the disk. The knurling so required can give rise to burrs and sharp edges which can injure the user. A further disadvantage of this structure is that the magnetic ring is positioned so that it is possible for it to abrade and scratch the surfaces of any adjacently positioned chips.
The Ring Chip structure taught by the patent to Gargione also fails to solve the problem of abrasion of other chips in that the metal ring is positioned to be in direct contact with surrounding chips. Furthermore, the positioning of the ring about the periphery of the chip exposes substantially all of the metallic surface to contamination, such as body salts from the fingertips of the user or materials on the game board surface. Moreover, the structure taught preferably uses metal which is substantially thinner than the plastic disk. This is so that the metal can be formed around the periphery of the disk. Due to the thinness of the metal and the manner in which the chips are placed on the playing surface, it is often the case that the chips become bent. In turn, this bending causes the metal to buckle, which causes the edge of the ring to rise up off of the disk. This raised edge can cause injury to the user's fingers. In the manufacturing of the Ring Chip it is difficult to consistently obtain a smooth crimp. Failure to do so results in raised edges which, in turn, have the potential to cause injury.